1. Bitwise AND (&): Convert a number to binary. and then operate. Align its digits. If the same bits are all 1. is 1. Otherwise it is 0; example:
$a = 5； 0101; $a = 35; 10 0011;
$b = 9 ; 1001; $b = 23; 01 0111;
$a & $b = 0001; decimal 1 $a & $b = 00 0011; decimal 3
2. Bitwise OR (|): Convert a number to binary. then perform an OR operation. Align its digits. If the same bit is not 1, it is 0. 1 otherwise; example:
$a = 5； 0101; $a = 35; 10 0011;
$b = 9 ; 1001; $b = 23; 01 0111;
$a & $b = 1101; decimal is 13 $a & $b = 110111; decimal is 55
3. Bitwise NOT (~): First make it clear. Computers only know two's complement. The positive complement code is the same as the original code. The complement of a negative number is the one's complement plus one. ~ is the inversion (1 becomes 0, 0 becomes 1);
Take negative 5 as an example:
Positive number 5 (32nd place): 00000000 00000000 00000000 00000101
Inverse code: 11111111 11111111 11111111 11111010
-5's complement: 11111111 11111111 11111111 11111011
Positive number 5 (32nd place): 00000000 00000000 00000000 00000101
Inverse code: 11111111 11111111 11111111 11111010
5's complement: 00000000 00000000 00000000 00000101
Example: $a = 5; $c = ~$a;
5's complement for ~ (to get the complement of a negative number) 111111111111111111111111111111010
Negative complement restore to one's complement (-1): 111111111111111111111111111111001
Get the original code of negative number: 000000000000000000000000000000110
Output: 6 false. A positive number ~ is a negative number; so it is -6;
The following uses -5 as an example: -5's complement 11111111 11111111 11111111 11111011
~ 00000000 00000000 00000000 00000100
Inverse 11111111 11111111 11111111 11111011
Original code 00000000 00000000 00000000 00000100
output: 4